Downhole Impression Imaging System and Methods Using Shape Memory Material

ABSTRACT

A system and method for obtaining an impression of an object in a remote environment. An impression block is affixed to a running string and disposed into the remote environment and used to form an impression. The impression block includes an impression section formed of a shape memory material that can be transformed between an original shape and a temporary shape.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to devices and methods used to assist inremoval of stuck tools or objects from a wellbore or other remotelocation by fishing.

2. Description of the Related Art

Fishing is used to remove tools or other objects that have become stuckwithin a wellbore. Stuck tools or objects can have irregular surfacesonto which it is difficult to latch a fishing tool. It is useful for anoperator to have information relating to the geometry of the stuckdevice or object so that appropriate fishing tool(s) can be used to besttry to remove the stuck device or object.

SUMMARY OF THE INVENTION

The invention provides devices and methods for creating athree-dimensional image or impression of a stuck tool or device in aremote environment, such as within a subterranean or subseahydrocarbon-production wellbore. In certain described embodiments, animpression block is provided that includes an impression section formedof a shape memory polymer material and a heating mechanism. The heatingmechanism is capable of heating the impression section to a transitiontemperature that allows the section to be deformed from an originalshape to a temporary deformed shape. In some embodiments, the heatingmechanism includes a heating filament that helps distribute heatingwithin the impression section. In other embodiments, the heatingmechanism is a chemical heating mechanism.

In a described method of operation, the impression block is incorporatedinto a running tool and disposed into a wellbore that contains a stucktool or object. The impression section of the impression block has aninitial shape and is preferably unheated so that it is at a temperaturethat is below its transition temperature. The impression block isbrought into contact with the stuck tool or object. The heatingmechanism is actuated to heat the impression section until it reachesits transition temperature. The impression section is then allowed toconform to the upper surfaces of the stuck tool or object to create animpression within the impression section. In particular embodiments,weight is applied to the running string to assist formation of theimpression.

Once the impression has been formed, the heating mechanism is turned offand the impression section cools. Upon cooling, the impression sectionmaintains the impression in its temporary shape. The impression block isthen removed from the wellbore. In one embodiment, the impression isused as a mold to create a positive 3D model of the upper surface of thestuck tool.

An alternative embodiment is described wherein the impression section isformed of a metallic shape memory material, such as alloy. The metallicshape memory material can be deformed from an original shape to atemporary shape below a transition temperature and will subsequentlytransition back to the original shape when heated up to or above atransition temperature. In particular embodiments, the metallic shapememory material is formed into an impression block that includes a thin,easily deformed element, such as a thin plate or mesh.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and further aspects of the invention will be readilyappreciated by those of ordinary skill in the art as the same becomesbetter understood by reference to the following detailed descriptionwhen considered in conjunction with the accompanying drawings in whichlike reference characters designate like or similar elements throughoutthe several figures of the drawing and wherein:

FIG. 1 is a side, cross-sectional view of an exemplary downholeimpression block for an impression imaging system constructed inaccordance with the present invention.

FIG. 1A is side, cross-sectional view of an alternative downholeimpression block for a downhole impression imaging system.

FIG. 1B is a side, cross-sectional view of a further alternativedownhole impression block.

FIG. 1C is a side, cross-sectional view of a further alternativedownhole impression block.

FIG. 1D is a side, cross-sectional view of a further alternativedownhole impression block which includes a chemical heating mechanism.

FIG. 2 is a side, cross-sectional view of an exemplary wellbore with astuck tool and a downhole impression imaging system constructed inaccordance with the present invention.

FIG. 3 is an enlarged, side, cross-sectional view of the wellbore withan exemplary impression imaging system being used to create animpression of an upper surface of the stuck tool.

FIG. 4 is an enlarged, side, cross-sectional view of the wellbore withthe impression imaging system of FIG. 3 now being removed from thewellbore.

FIG. 5 is a side, cross-sectional view of an alternative embodiment foran impression imaging system which incorporates an impression blockhaving an element formed of a metallic shape memory alloy.

FIG. 6 is a side, cross-sectional view of the impression imaging systemshown in FIG. 5, now with the impression block having been deformed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates an exemplary impression block 10 in accordance withthe present invention. The impression block 10 includes a retainingsection 12 having a threaded portion 14. The threaded portion 14 isprovided so that the impression block 10 can be affixed to a runningstring, such as running string 16 in FIG. 2. A recess 18 is formedwithin the retaining section 12, and an impression section 20 isdisposed within the recess 18. The impression section 20 is formed orsubstantially formed of a shape memory material, such as a polymer, thatcan be changed between an original shape and a temporary shape while ator above a predetermined transition temperature and that will remain ineither the original or temporary shape when at a temperature that isbelow the transition temperature. In particular described embodimentsthe shape memory material is a shape memory polymer, which may be one ofthe polyurethane materials described in U.S. Pat. No. 8,048,348 issuedto Duan et al. U.S. Pat. No. 8,048,348 is owned by the assignee of thepresent invention and is hereby incorporated by reference in itsentirety. It is noted that the transition temperature of the polymersection 20 should be higher than the highest temperature that isexpected within the wellbore environment into which the impressionsection 20 will be placed.

The impression block 10 also includes a heating mechanism 22 that isoperable to heat the impression section 20. FIG. 1 shows an exemplaryheating mechanism 22 that can be selectively actuated by being energizedto heat the impression section 20 up to its transition temperature andde-energized to allow the to impression section 20 to cool below itstransition temperature. In the depicted embodiment, the heatingmechanism 22 is electrically energized and can be turned on or off fromthe surface of a wellbore. An electrical line 24 is shown that is usedto supply electrical power to the heating mechanism 22.

FIG. 1A depicts an alternative embodiment for an impression block 10 awherein the heating mechanism 22 has a resistive heating filament coil23 that extends annularly in a helical manner proximate the outercircumference of the impression section 20. The resistive coil 23 willheat up when the heating mechanism 22 is energized and serves to helpdistribute the heat throughout the impression section 20. The embodimentdepicted in FIG. 1A might be particularly useful where the stuck tool ordevice has a tubular shape. FIG. 1B illustrates a further alternativeembodiment for an impression block 10 b wherein the heating mechanism 22has two resistive coils 23 a and 23 b. The coil 23 b is disposedcoaxially within the outer coil 23 a. FIG. 1C depicts a furtherembodiment for an impression block 10 c wherein a number of strands 23 cof resistive heating filaments extend through portions of the impressionsection 20.

FIG. 1D depicts an alternative embodiment for an impression block 10 dwherein the impression section 20 contains a heating mechanism in theform of a chemical heating mechanism, generally shown at 26. In thedepicted embodiment, the chemical heating mechanism 26 includes twochemical reservoirs 27, 28 that are separated from one another by afrangible barrier 29. The reservoirs 27, 28 each contain a chemicalthat, when mixed with the chemical from the other reservoir, create anexothermic reaction that will heat the impression section 20. Thebarrier 29 can be broken by application of pressure to the impressionblock 10 d from the surface or in other ways known in the art. Anexample of chemicals that could be combined to create an exothermicreaction is calcium chloride and water. A reaction of these chemicals istypically capable of heating it environment to a temperature of about194° F. (90° C.) from an ambient temperature of 68° F. (20° C.).

It should be understood that any of the impression blocks 10 a, 10 b, 10c or 10 d may be used interchangeably with the impression block 10 inthe impression imaging system that will be described and depicted inFIGS. 2-4.

FIG. 2 depicts a hydrocarbon-production wellbore 30 that has beendrilled through the earth 32 from the surface 34. It is noted that theimpression block 10 and impression imaging system and method of thepresent invention are shown being used in conjunction with ahydrocarbon-production wellbore 30, in fact, systems and methods of thepresent invention may be used to obtain impressions of objects and toolsin any remote or subterranean environment. The wellbore 30 has beenlined with metallic casing 36. A tool 38 is stuck within the wellbore30. Although a wellbore tool is shown, those of skill in the art willunderstand that the systems and methods of the present invention mayalso be used with objects other than tools. The tool 38 presents anirregular upper surface 40. FIG. 2 also shows a downhole impressionimaging system 42 that has been constructed in accordance with thepresent invention. The impression imaging system 42 includes a runningstring 44 that extends downwardly from the surface 34 of the wellbore30. The running string 44 is preferably formed of interconnectedsections of production tubing, as is known in the art. However, therunning string 44 might also be formed of coiled tubing or of othermaterials known in the art. It is preferred that the construction of therunning string 44 be such that weight can be applied to it at surface.An impression block 10 is affixed to the lower end of the running string44.

FIG. 2 illustrates the downhole impression imaging system 42 in a run-inposition wherein the heating mechanism 22 is preferably not energized,and the impression block 10 has not yet been placed in contact with theupper surface 40 of the stuck tool 38. While FIG. 2 depicts a generallocation for the heating mechanism 22 within the impression section 20,it should be understood that the specific location within the impressionsection 20 may vary if desired. FIG. 3 illustrates the impressionimaging system 42 being used to create an impression of the uppersurface 40 of the stuck tool 38. Prior to forming the impression, theheating mechanism 22 is energized to heat the impression section 20 upto or above the predetermined transition temperature, which permits thepolymer section 20 to be deformed and generally conform to the shape ofthe upper surface 40. Once heated, the impression imaging system 42 ismoved downwardly so that the impression section 20 is placed intocontact with the surface 40. Preferably, some weight is applied to therunning string 44 in order to create an accurate impression of theunseen surface 40 within the impression section 20. The deformed shapebecomes the temporary shape of the impression section 20.

Once the impression is created within the impression section 20, theheating mechanism 22 is deenergized so that the impression section 20can cool below its transition temperature. Once cooled, the impressionsection 20 will remain in the temporary shape formed by the uppersurface 40. Then, the impression imaging system 42 is removed bywithdrawing the running string 44 from the wellbore 30, as illustratedby the arrow 46 in FIG. 4. Because the impression section 20 remainsbelow the transition temperature, it will remain in the temporary shape.

Once, the impression imaging system 42 has been removed from thewellbore 30, the impression block 10 can be removed and inspected by auser to determine the optimal fishing tool(s) to be used to engage andremove the stuck tool 38 from the wellbore. If desired, the impressedimpression section 20 may be used as a mold to form a positivethree-dimensional representation of the upper portion of the stuck tool38.

It is noted that the impression block 10 can be returned to its originalcondition and reused. In order to do this, the heating mechanism 22 isreenergized to heat the impression section 20 up to or over thetransition temperature. The impression section 20 will return to itsoriginal shape. Thereafter, the heating mechanism 22 can be deenergizedso that the impression section 20 can cool, remaining in its originalshape. The above-described process may then be used with another stucktool or object to obtain another impression.

FIG. 5 illustrates an alternative embodiment for a downhole imagingimpression block 10 e which incorporates an impression section 20 e thatis formed of a metallic shape memory alloy. The metallic shape memorymaterial can be deformed from an original shape to a temporary shapebelow a transition temperature and will subsequently transition back tothe original shape when heated up to or above a predetermined transitiontemperature. Examples of suitable metallic shape memory alloys includenickel-titanium, copper-zinc-aluminum-nickel and copper-aluminum-nickel.In the depicted embodiment, the impression section 20 e is a mesh thatis fashioned of metallic shape memory alloy filaments. In the depictedembodiment, the mesh of the impression section 20 e is roughly formedinto a hollow cylinder. As an alternative to mesh, metallic shape memoryalloy could also be fashioned into thin plate and then formed into ahollow cylinder for use as the impression section 20 e. In the depictedembodiment, an electrical conduit 46 interconnects the heating mechanism22 with the impression section 20 e so that electrical power can betransmitted to the impression section 20 e, thereby causing the mesh toheat when energized.

FIG. 6 shows the impression block 10 e having been brought into contactwith the upper surface 40 of the stuck tool 38 with weight or forcehaving been applied to the running string 44 so that the impressionsection 20 e has been deformed from its original shape (FIG. 5) to atemporary shape. The temporary shape will be the impression of the uppersurface 40 of the stuck tool 38. In the described embodiment, thedeformation of impression block 10 e will occur while the impressionsection 20 e is not heated above its transition temperature.

In subsequent operation, the impression block 10 e is brought to thesurface. The impression section 20 e is then examined to provide anindication of the shape of the upper surface 40 of the tool 38. Theheating mechanism 22 can then be heated to cause the impression section20 e to return to its original shape. Thereafter, the impression block10 e can be reused.

It should be understood that the systems and methods of the presentinvention are useful in both land-based subterranean wellbores as wellas subsea wellbores. In addition, the systems and methods of the presentinvention are useful in other subterranean and remote locations.

The foregoing description is directed to particular embodiments of thepresent invention for the purpose of illustration and explanation. Itwill be apparent, however, to those skilled in the art, that manymodifications and changes to the embodiment set forth above are possiblewithout departing from the scope and the spirit of the invention.

1-16. (canceled)
 17. A method for obtaining an impression of an object in a remote environment comprising the steps of: disposing an impression block into the remote environment, the impression block having an impression section that is formed of a shape memory material that may be changed between an original shape and a temporary shape when at or above a predetermined transition temperature and which retains either the original or temporary shape when below the transition temperature; heating the impression block to the transition temperature; forming an impression of the object within the impression block; and cooling the impression block below the transition temperature.
 18. The method of claim 17 wherein the impression block is disposed into the remote environment on a running string.
 19. The method of claim 17 wherein the remote environment comprises a subterranean or subsea hydrocarbon-production wellbore.
 20. The method of claim 17 wherein the step of heating the impression block to the transition temperature further comprises actuating a heating mechanism.
 21. A method for obtaining an impression of an object in a remote environment comprising the steps of: disposing an impression block into the remote environment, the impression block having an impression section that is formed of a shape memory material that may be changed between an original shape and a temporary shape and that is returned to the original shape from the temporary shape when heated at or above a predetermined transition temperature; forming an impression of the object within the impression block, the impression providing the temporary shape; and removing the impression block from the remote environment.
 22. The method of claim 21 further comprising the step of heating the impression block to the transition temperature to return the impression block to its original shape. 